*2.3. Mechanical Properties*

A film's greatest ability to endure applied tensile stress is measured by its tensile strength (TS), while its capacity to stretch is shown by its elongation percentage (EB%) [38]. Films with good mechanical characteristics are advantageous in industrial manufacturing, packing, transporting, and end-use applications. A comparative statistical analysis was done on the mechanical characteristics of chitosan gel films that contained various EPPE concentrations (Table 3). When the EPPE percentage rose from 0 to 5%, the TS and EB% both improved considerably, from 21.30 ± 1.191 to 26.87 ± 1.38 MPa and from 53.42 ± 3.02 to 58.64 ± 3.00%, respectively. The interaction between both the CH matrix and the polyphenolic components from EPPE may be responsible for the impact of EPPE inclusion on the enhancement in the mechanical characteristics of the related films. These interactions may result in tighter polymer chain-to-chain connections and better interfacial bonding between the CH monomers and the EPPE in the gel film layer, both of which increase the resistance against mechanical stress [39]. Similar findings were made by Balti et al. [40] and Siripatrawan and Harte [29], who noted that TS and EB increased as *spirulina* extract or green tea content increased from 0 to 5%.


**Table 3.** Mechanical properties of chitosan films modified with different percentages of EPPE.

Data are presented as mean <sup>±</sup> SD. Means with different superscripts (a–d) in lowercase letters in a column are significantly different at *p* < 0.05.
